The present invention relates to a system and method of venting refrigerant from a high pressure region adjacent a contacting shaft seal to a lower pressure region to reduce the pressure differential across the seal.
Screw compressors are positive displacement machines that work on the principle of volume reduction to increase refrigerant pressure. Two intermeshing helical screws within a compression chamber interact to convert low pressure refrigerant at the inlet to high pressure refrigerant at the discharge. The helical screws rotate about rotor shafts that are supported by bearings located within a bearing housing. Due to the pressure difference between the high pressure end of the compression chamber and the bearing housing, refrigerant can leak from the compression chamber through the path created by penetration of each rotor shaft into the bearing housing. Shaft seals are typically utilized to minimize this leakage.